NOAA Weather Radio is a service of the National Oceanic and Atmospheric Administration (NOAA) of the U.S. Department of Commerce. As the “Voice of the National Weather Service”, it provides continuous broadcasts of the latest weather information from local National Weather Service offices. Weather messages are repeated every 4 to 6 minutes, and are routinely updated every 1 to 3 hours or more frequently in rapidly changing local weather, or if a nearby hazardous environmental condition exists. The service operates 24 hours daily. The regular broadcasts are specifically tailored to weather information needs of the people within the service area of the transmitter. For example, in addition to general weather information, stations in coastal areas provide information of interest to mariners. Other specialized information, such as current conditions and forecasts, may be broadcast.
During severe weather, National Weather Service forecasters can interrupt the routine weather broadcasts and insert special warning messages concerning imminent threats to life and property. The forecaster can also add special signals to warnings that trigger “alerting” features of specially equipped receivers. This is known as the tone alert feature, and acts much like a smoke detector in that it will alarm when necessary to warn of an impending hazard. Currently, all receivers equipped with the tone alert feature within the listening area will alarm when a warning is issued. However, in the future, only receivers located in the warned area (normally a specific county or counties) will alarm. This feature is referred to as Specific Area Message Encoding (SAME), and will be the primary activator for the new Emergency Alert System currently being implemented by the Federal Communication Commission.
Under a January 1975 White House policy statement, NOAA Weather Radio was designated the sole government-operated radio system to provide direct warnings into private homes for both natural disasters and nuclear attack. This concept is being expanded to include warnings for all hazardous conditions that pose a threat to life and safety, both at a local and national level. NOAA Weather Radio currently broadcasts from over 400 FM transmitters on seven frequencies in the VHF band, ranging from 162.400 to 162.550 megahertz (MHz) in fifty states, Puerto Rico, the Virgin Islands, Guam, and Saipan. These frequencies are outside the normal AM or FM broadcast bands.
Special radios that receive only NOAA Weather Radio, both with and without the tone alert feature, are available from several manufacturers. The radios can usually be found at most department and electronics stores. In addition, other manufacturers are including NOAA Weather Radio as a special feature on an increasing number of receivers. NOAA Weather Radio capability is currently available on some automobile, aircraft, marine, citizens band, and standard AM/FM radios, as well as communications receivers, transceivers, scanners, and cable TV.
By nature and by design, NOAA Weather Radio coverage is typically limited to an area within 40 miles, using 500 watt transmitters, of the transmitter. The quality of what is heard is dictated by the distance from the transmitter, local terrain, and the quality and location of the receiver. In general, those on flat terrain or at sea, using a high quality receiver, can expect reliable reception far beyond 40 miles. Those living in cities surrounded by large buildings, and those in mountain valleys, with standard receivers may experience little or no reception at considerably less than 40 miles. If possible, a receiver should be tested in the location where it will be used prior to purchase.
NOAA Weather Radio is directly available to approximately 70 to 80 percent of the U.S. population. The National Weather Service is currently engaged in a program to increase coverage to 95 percent of the population.
Using an existing NOAA issued weather radio; the user of this service is required to tune the weather radio to a given frequency based on their location before the radio will work. Once working, the weather radio will notify the users covering an area of approximately 40 miles radius from the transmitter, see the NOAA Weather Radio coverage maps at http://www.weather.gov/nwr/Maps/. Currently, the NOAA Weather Radio Network includes 1000 transmitters, covering all 50 states, adjacent coastal waters, Puerto Rico, the U.S. Virgin Islands, and the U.S. Pacific Territories.